Benchmark: Return true vs empty body

Script Preparation code:

var notDefined;
var defined = 1;

var emptyFunc = function() {};
var trueFunc = function() { return true; }
var undefinedFunc = function() { return undefined; }
var nullFunc = function() { return null; }
var notDefinedFunc = function() { return notDefined; }
var definedFunc = function() { return defined; }
var staticFunc = function() { return 1; }
var localUndefinedFunc = (function() {
  var notDefinedAgain;
  
  return function() {
  	return notDefinedAgain;
  }
})();

Tests:

localUndefinedFunc
localUndefinedFunc();
wrapped localUndefinedFunc
(localUndefinedFunc());

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
localUndefinedFunc
wrapped localUndefinedFunc

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 8 years ago)

User agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/53.0.2785.116 Safari/537.36

Browser/OS: Chrome 53 on Windows 7

View result in a separate tab

Test name	Executions per second
localUndefinedFunc	9397231.0 Ops/sec
wrapped localUndefinedFunc	9252704.0 Ops/sec

Autogenerated LLM Summary (model llama3.2:3b, generated 2 months ago):

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and its test cases to understand what is being tested.

**Benchmark Definition JSON**

The benchmark definition represents a JavaScript function that is being tested for performance. The functions are:

1. `localUndefinedFunc`: This function returns `notDefinedAgain` within itself, creating a local scope.
2. `definedFunc`: This function returns the value of `defined`, which is set to 1.
3. `trueFunc`: This function simply returns `true`.
4. `emptyFunc`: This function does nothing (i.e., it has an empty body).
5. `undefinedFunc`: This function returns `undefined`.
6. `nullFunc`: This function returns `null`.
7. `notDefinedFunc`: This function returns `notDefined`, which is set to undefined.
8. `staticFunc`: This function returns a static value of 1.

**Options Compared**

The benchmark compares two approaches:

1. **Direct function call**: `localUndefinedFunc();`
2. **Wrapped function call**: `(localUndefinedFunc());`

These differences are what the benchmark aims to measure and optimize.

**Pros and Cons of Different Approaches**

1. **Direct Function Call (localUndefinedFunc())**
	* Pros: Faster, as it directly calls the function without wrapping.
	* Cons: May be less efficient due to potential overhead from parsing the wrapped expression.
2. **Wrapped Function Call ((localUndefinedFunc()))**
	* Pros: May be more robust, as it avoids potential issues with scope and variable hoisting in JavaScript.
	* Cons: Slower, as it involves wrapping the function call in parentheses.

**Library Usage**

None of the test cases explicitly use any libraries. However, the benchmark definition includes a script preparation code that defines various variables and functions, which may be part of a custom library or utility module.

**Special JS Feature/Syntax**

The benchmark uses a feature called **Immediately Invoked Function Expression (IIFE)**, which is a special syntax for creating functions that are executed immediately. In this case, `localUndefinedFunc` is defined using an IIFE:
```javascript
var localUndefinedFunc = (function() {
  var notDefinedAgain;
  return function() {
    return notDefinedAgain;
  };
})();
```
This creates a new scope for the inner function and returns its reference.

**Other Alternatives**

If you were to modify or extend this benchmark, some alternative approaches could be explored:

1. **Use of `let` or `const` instead of `var`**: This might affect the performance of the wrapped function call.
2. **Inlining functions**: The benchmark could test whether inlining functions improves performance.
3. **Using a different type of function (e.g., arrow function)**: The benchmark could compare the performance of direct function calls versus arrow function calls.

By exploring these alternative approaches, you can gain a deeper understanding of JavaScript performance optimization techniques and how they apply to specific use cases.

Related benchmarks:

Return true vs empty body (version: 0)

Comparing performance of: localUndefinedFunc vs wrapped localUndefinedFunc

Created: 8 years ago by: Guest

Jump to the latest result

localUndefinedFunc

wrapped localUndefinedFunc

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 2 months ago):